<html>
    <head>
        <meta charset="UTF-8">
        <title>hide and show</title>
        <style type="text/css">
                div{
                    width:200px;
                    height: 200px;
                    background: greenyellow;
                    font-size: 30px;
                    color: red;
                }
            
        </style>
        <script type="text/javascript" src="JQuery-js文件/jquery-3.3.1.js"></script>
        <script type="text/javascript">
            function fun1(){
                $("div").hide(3000);
            }
            function fun2(){
                $("div").show(3000);
            }
        
        </script>
    </head>
    <body>

        <div>
            我是一个div
        </div>
        <input type="button" value="隐藏DIV" onclick="fun1();"/>
        <input type="button" value="显示DIV" onclick="fun2();"/>
    </body>
</html>